Refrigerator control



Nov. 7, 1933. J. J. BAUMAN 1,934,608

REFRIGERATOR CONTROL Original Filed June 17.,1932 2 Sheets-Sheet lWIITNESSES: INVENTOR X- fi/m J. J. Baum/m BY 0/. d5, 6 ATTORNEY Nov. 7,1933- .1. J. BAUMAN REFRIGERATOR CONTROL Original Filed June l7h1932 2Sheets-Sheet 2 INVENTOR J.J.BnuMAN BY a rfi/M I ATTORNEY Patented Nov.7, 1933 UNITED STATES PATENT OFFICE REFRIGERATOR CONTROL PennsylvaniaOriginal application June 17, 1932, Serial No. 617,909. Divided and thisapplication June 8, 1933. Serial No. 674,917

7 Claims. (Cl. 62-4) My inventionrelates to a control mechanism forrefrigerating systems and it has for an object to provide a simplifiedmechanism that will be reliable in operation and inexpensive tomanufacture. This is a division of my copending application, Serial No.617,909, filed June 17, 1932 for Refrigerator control and covers thedefrosting features of my invention.

In refrigerators of all classes and particularly in household types, itis desirable to maintain normally a predetermined mean temperaturetherein. For example, if it is desired to maintain the cooling unit orheat absorbing unit of the refrigerating system at a mean temperature oftwelve degrees F., the control mechanism should be capable ofautomatically starting the operation of the refrigerating systemwhenever the cooling unit reaches a temperature of, for example, 20 F.,and of stopping the operation of the system whenever the temperature ofthe cooling unit is reduced to, for example, 4 F. It is also desirableto be able to change this predetermined mean temperature at will and tooperate the refrigerator periodically at a temperature suificiently highto defrost portions of the system. In other words, to maintain thecooling or heat absorbing unit at a mean temperature which issufficiently high to melt frost off the cooling unit which hasaccumulated thereon during operation at relatively lower meantemperature. These advantages are obtained by my novel control mechanismwhen applied to refrigerators having a cabinet compartment and a machinefor producing refrigeration therein.

In practicing my invention I provide an electric switch for controllingthe operation of the machine and a thermostatic element for actuatingthe switch in response to the cabinetcompartment temperatures, wherebythe compartment is maintained between predetermined high and lowtemperatures. Adjustments are provided on the control mechanism forchanging these predeter- 'mined temperatures, which changes are madewithout the use of a complicated system of springs or other biasingdevices. One of the temperature adjustments is readily accessible to theoperator and changes the mean temperature to r be maintained within thecabinet, the cabinet unit are sufiiciently high to defrost portions ofthe system such as, for example, the evaporator, with continuance ofcycling to maintain a mean temperature or temperature range high enoughto provide defrosting but low enough to prevent rapid food spoilage. Forexample, if the control mechanism does not automatically start therefrigerating system until the temperature of the cooling or heatabsorbing unit is, for example, 42 F., and automatically stops therefrigerating system when the cooling or heat absorbing unit has atemperature of, for example, 30 F., the mean temperature will be such asto effect defrosting of the cooling or heat absorbing unit, but

I the resultant temperature in the cabinet will always be suhicientlylow to retard food spoilage.

For the purposes of this specificatiomthe word cycle includes one activeperiod of the refrigcrating system plus either the preceding orsucceeding inactive period of the refrigerating system; by continuanceof cycling or continuous cycling is meant automatic starting andstopping of the system and involving a series of active periodsalternated with inactive periods of the refrigerating system.

More particularly, my invention comprises a temperature controlmechanism embodying a switch opened and closed by a rockable or tiltablemember, the latter being operated by a member or lever movable inresponse to thermal conditions, together with means for advancing orretarding tilting or rocking of the tiltable or rockable member withrespect to the operating range of movement of the movable member orlever. The movable member or lever is moved in one direction by biasingmeans, for example, a spring, and in the other direction by means, suchas a bellows, responsive to temperature. The biasing means or spring maybe adjusted to regulate the general desired setting of the mechanism,and further regulation may be secured by the advancing and retardingmeans to raise or lower the desired temperature. When the controlmechanism is used to control a mechanically operated refrigerator,adjustment of the advancing and retarding means in the advance directionlowers the temperatures at which the switchis closed to secure operationand at which the switch is opened to interrupt operation, and adjustmentin the retard direction has the contrary effect. By ad-- justment inthis way of the temperatures at which the switch is closed and opened,it is possible to have a refrigerator operated at such a hightemperature range that defrosting of the evaporator and associatedelements may be effected with cycling thereof, whereby, duringdefrosting, the attainable upper temperature will be limited and foodspoilage minimized. I also provide means for limiting motion of thetemperature responsive movable member or lever so that, with theadvancing and retarding adjustment means in full retarded position,closing of the switch is prevented, this being useful in effecting rapiddefrosting; and also, I preferably provide means for limiting motion ofthe temperature responsive movable member or lever so that, with theadvancing and retarding adjustment means in full advance position,opening of the switch is prevented, this being useful in effecting rapidfreezing or cooling.

It is another object of my invention to provide a control mechanism fora mechanical refrigerator capable of regulation to obtain defrostingwith continuance of cyclic operation.

It is a further object of the invention to provide a temperature controlmechanism having adjusting means for advancing and retarding opening andclosing of a switch relative to movement of the temperature responsivemeans.

It is a still further object of my invention to provide a temperaturecontrol mechanism for a refrigerator having a series of adjustedpositions for cycling the machine to maintain progressively increasingtemperatures within the refrigerator, the highest of which is effectiveto defrost the evaporator of the refrigerator.

It is a further object of my invention to provide a mechanical orelectrical refrigerator with control mechanism capable of being adjustedto interrupt operation or to maintain continuous operation, or both.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawings, forming a part of this application, in which:

Fig. 1 is a view of a refrigerator having my control mechanism appliedthereto;

Fig. 2 is a front elevation of my novel control mechanism;

Fig. 3 is a plan with parts broken away of the apparatus shown in Fig.2;

Fig. 4 is a view similar to Fig. 2 but with parts broken away;

Fig. 5 is a section taken along the line V-V of Fig. 4;

Figs. 6, '7 and'8 are diagrammatic views of parts of the mechanism invarious positions.

Referring to Fig. 1, I show a refrigerator 10, including a cabinet 11, acooling compartment 12, and an evaporator 13 in heat exchange relationtherewith. A motor-compressor unit 14 for circulating refrigerant ispreferably mounted on the cabinet 11 and is operatively controlled by aswitch 23 (Fig. 4), included in the mechanism 15. The switch 23 closesand opens the electric circuit of the motor compressor unit 14 toinitiate and terminate operation of the same. The well-knowncompression-expansion cycle is used to provide refrigeration within thecabinet 11. Refrigerant vapor is withdrawn from the evaporator 13 by themotor-compressor unit 14 and forced under pressure to a condenser 16where it is condensed. The condensed refrigerant then passes through anexpansion device 17 to the evaporator whereit is vaporized, abstractingheat from the cooling compartment 12 in a wellknown manner. The cycle isrepeated so long as the motor-compressor unit 14 operates. A fan 18 maybe used to circulate a cooling medium through the condenser to assist incooling the refrigerant.

The control mechanism 15 includes a base 20 and acover or hood 21enclosing a suitable switch, for example, the fluid or mercury switch23, which is opened and closed due to rocking or tilting movement of arockable or tiltable member; mechanism operating in response to coolingunit temperature to rock or tilt the tiltable member to open and closethe switch; and means, preferably manually operable or settable, toadvance or retard closing and opening of the switch in response tomovement of the mecha nism due to cooling unit temperature.

The mechanism operating in response to cool ing unit temperatureincludes a frame or pedestal 24 secured to the base 20 and consistingpreferably of side members 25 and 26 and upper and lower crossmembers-27 and 28, respectively. A movable member, for example, a lever29. is pivoted at 30 to the pedestal side member 25 and extends acrossthe space between the side members and beyond the other side member 26.

Biasing means, for example, a spring 31, exerts force on the movablemember or lever and tends to cause it to move in one direction, andtemperature responsive means, for example, the bellows.32, opposes thespring and causes the lever or movable member to move in the otherdirection against the force of the spring.

The temperature responsive means or bellows 32 has a tube 32a securedthereto, which tube 32a extends Within the cooling compartment 12' andis subjected to the temperature of the cooling unit. The bellows 32 andtube 32a define a chamber within which a volatile gas is confined.

As the pressure of gas varies with the temperature of the cooling unit13, the amplitude of the bellows 32 will depend on the pressure of theconfined gas and incidental cooling means temperature.

The outer end of the lever 29 is pivotally connected at 33 to therockable and tiltable member 34, which rocks or tilts about the fulcrum35 to open and close the switch. It will, therefore, be apparent thatchange in temperatrue results in motion of the lever 29 and that thisbrings about tilting or rocking of the tiltable or rockable member 34 toopen and close the switch. The positions assumed by the bellows 32,lever 29, and the switch 23 when the latter is open and closed areshown, respectively, in Figs. 4 and 6.

Preferably, as illustrated, the biasing means or spring 31 is arrangedabove the lever 29 and in the space between the latter and the uppercross member 2'7, the upper cross member carrying an adjustable follower36 for adjusting the tension of the spring.

The bellows 32 is arranged underneath the lever and between the latterand the lower cross member 28 of the pedestal.

By varying the force or compression of the spring, the temperatures atwhich the switch is closed or opened may be raised or lowered. For

example, if it is desired to set the control mechanism to close theswitch at a lower temperature, the spring force is diminished and viceversa. The spring is adjusted for a normal operating condition andvariability is secured by mechanism associated with the rockable ortiltable member 34, serving to advance or to retard openirg and closingof the switch with respect to 15 movement of the lever 29, and whichwill now be described.

The adjustment for securing the advance and retard efiect of opening andclosing of the switch with respect to the operating range of movementofthe temperature responsivemember includes a longitudinal slot 87provided in the rockable or tiltable member 34 and having the fulcrumpin 35 disposed therein. If the fulcrum pin is lowered, with the lever29 in a given position, it will be apparent that the rockable member orcradle 34 will be moved angularly in a counter clockwise, orswitch-closing, direction about the pivotal connection with the resultthat both opening and closing of the switch may be secured with lowerpressure exerted by the bellows, and, therefore, with maintenance oflower temperature in the refrigerator. On the other hand, as the fulcrumpin 35 is ,raised, greater upward movement of the lever 29 is requiredto open and close the switch, with the result that the opening andclosing temperatures are proportionately increased. In Fig. '7, thefulcrum pin is shown in its lowermost position while in Fig. 8 it is inits uppermost position.

The fulcrum pin 35 is preferably raised and lowered for the purposesindicated by a lever 38 pivoted at 39 on extension 3901. fixed to sidemember 26. The outer end of the lever 38 has a fulcrum pin 35 mountedthereon, the lever being biased upwardly by a spring 40 and being moveddownwardly by a manually settable cam 41 cooperating with the pin 41a,the cam 41 having an operating shaft 42 carried'by the bracket 43attached to the pedestal structure. The spring 40 has one'of its endssecured to an extension 40a which is fixed to side member 26. The camhas such a peripheral contour that the desired range of upward anddownward movement of the fulcrum pin 35 is secured for desired operatingconditions. Preferably, the cam is so. designed and the other elementsare so constructed and arranged that, when the fulcrum pin is in anupper position, the temperature at which the switch is opened and closedwill be sufiiciently high to assure of defrosting with continuation ofcycling.

An upper adjustable abutment 44 cooperates with a projection 29a securedto and extending laterally from the lever 29 to limit upward motionthereof; and this abutment is preferably so adjusted that, with theportion of the cam of minimum radius cooperating with the lever pin 41a,the rockable or tiltable member cannot be moved in a counterclockwisedirection sufficiently to close the switch. (See Fig. 8). Also, a lowerabutment 45 preferably cooperates with the projection 29a of the lever29 to limit downward motion of the latter, whereby, with the fulcrum pin35 in its lowermost position, the lever 29 cannot move downwardly in aclockwise direction sufficiently to open the switch, this operationbeing desirable when most rapid cooling and freezing is desired. (SeeFig. 7.)

The lever 29 includes means providing for adjustment of its length,whereby the pivotal connection thereof withrespeot to the tiltable orrockable member may be moved inwardly or outwardly from the fulcrum pin35 to change the ratio of angular movement of the lever 29 to angularmovement of the tiltable or rockable member necessary to open or closethe switch. With lengthening of the lever, greater angular movement isnecessary to secure movement of the rockable or tiltable member througha predetermined angle and vice versa. This adjustment makes possiblevariation of the temperature difference necessary to secure opening andclosing of the switch. Preferably, in order to provide for thisadjustment, the lever 29 has a vertically extending portion 46 to theupper end of which is connected the yoke 47. A movable yoke 48, has ears49 cooperating with the first yoke to maintain the yokes in alignment. Ascrew 50 extends outwardly from the base portion of the yoke 47 andthrough an opening 500. provided in the base portion of the adjustableyoke 48, nuts 51 and 52 being arranged in opposite sides of the baseportion of the yoke 48 and providing for securement of the yokes in anydesired relative position.

.Compactness of the apparatus is secured by overlapping of operatingparts and by having all of the moving parts carried by a single standardor pedestal structure. It will be seen that the lever 29 extendsupwardly and that the arms of the yoke 48 are curved outwardly anddownwardly with the result that the outer ends of such arms may beconnected to the outer end of the rockable member or cradle 34 disposedbeneath the lever, whereby the lever and the cradle are disposed inoverlapping relation.

Referring to Fig. 2, a pointer 54 and a dial 55 are arranged exteriorlyof the cover 21 for the convenience of the operator. Suitable markingsare provided on the dial 55 to indicate conditions to be effected by themechanism. From the structure hereinbefore described, it will beapparent that the cam is constructed and arranged to provide for thefull range of different operating adjustments. When the cam portion ofminimum radius bears on the pin 41a, the fulcrum pin 35 will be in itsuppermost position, as shown in Fig. 8, in which position maximumexpansion, corresponding to the highest temperature will be required inorder to close the switch; and, if the abutment 44 is adjusted to limitupward movement ofthe lever 29, closure of the switch may be prevented.With a portion of the cam of somewhat larger radius bearing on the pin41a, the fulcrum pin 35 will be lowered, with the result that openingand closing of the switch takes place at relatively high temperatures,which temperatures may be above that corresponding to the freezing pointof water at the exterior surfaces of the evaporator and associatedparts. With such an adjustment, defrosting may be effected with cyclingof the refrigerator. As portions of the cam of increasing radius arecaused to bear on the pin 41a, opening and closing of the switch takesplace at lowered temperatures until minimum temperature conditions arereached when the cam portion of maximum radius is bearing on the pin4111. With the cam portion of maximum radius bearing on the pin 41a andwith suitable adjustment 0f the lower abutment 45, downward movement ofthe lever 29, in consequence of decreasing temperature, is limited sothat there is insufficient movement of the lever to open the switch,with the result that the refrigerator may be operated continuously,without cycling, in or-' der to efiect quick cooling or freezing.Therefore, referring again to Fig. 2, the position indicated defrost isthe position referred to above where a portion of the cam of smallradius is efcated 1, 2, 3, 4, and 5 correspond to cam portions'ofincreasing radius, which, as hereinbefore pointed out, provide forcycling of the refrigerator to maintain lower and lower temperatures;the position indicated 6 corresponds to a cam portion of still largerradius, as shown in Fig. 7, where the parts of the mechanism are sorelated that, due to cooperation of the lower abutment 45 with the lever29, opening of the switch is prevented and continuous operation issecured without cycling; and the position indicated off corresponds tothe portion of the cam of minimum radius, and is effective, due to thecooperation of the upper abutment 44, to prevent closure of the switch.(See Fig. 8.)

It will be apparent from the foregoing that I have devised a novelcontrol mechanism for a mechanical refrigerator having a plurality ofadjustments for changing the maximum and minimum operating temperaturesof a refrigerator with an adjustment for changing the operatingtemperature range; all of said adjustments being of simple construction,each functioning without affecting the other and without the use of acomplicated system of biasing devices. It will be seen also that I haveprovided a control mechanism wherein a plurality of positions forcontinuously cycling the refrigerating machine to maintain va rious meancabinet temperatures are provided, one of which will effect defrostingof the evaporator and all of which are manually obtainable by a commonadjusting means. I have shown my novel control mechanism applied to acompression type refrigerator, but it will be understood that othertypes of refrigerating machines may be controlled thereby.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof, and I desire, therefore, that only such limitations shall beplaced thereupon as are imposed by the prior art or as are specificallyset forth in the appended claims.

What I claim is:

1. In a refrigerating system, the combination of a cabinet, anevaporator for absorbing heat from the cabinet, an intermittentlyoperated refrigerating machine for circulating refrigerant through theevaporator and a mechanism adjustable to a series of positions foreffecting continuous cycling of the machine at progressively increasingmean evaporator temperatures, the maximum mean temperature obtained bycontinuous cycling being effective to remove frost from the evaporatorwhich has accumulated thereon at the lower mean evaporator temperaures.

2. In a refrigerating apparatus for preserving food-stuffs, thecombination of a refrigerator cabinet, a cooling unit in the cabinet forabsorbing heat therefrom, a refrigerating mechanism for circulating arefrigerant through the cooling unit, and a control mechanism for therefrigerating mechanism including means to effeet cycling of themechanism to maintain the sorbing heat therefrom, a refrigeratingmechanism for circulating a refrigerant through the cooling unit, and acontrol mechanism for the refrigerating mechanism including means toeffect cycling of the mechanism to maintain the cooling unit atrelatively low refrigerating temperatures, whereupon .frost incidentallyaccumulates on the cooling unit, and also including means to effectcontinuous cycling of the mechanism to maintain a relatively higherrefrigerating temperature in the cooling unit sufficient to remove or toretard the accumulation of frost on the cooling unit, said lattertemperature being sufficiently low for preserving food-stuffs and commonmeans manually operable for obtaining either condition of operation ofthe refrigerating mechanism.

4. In a refrigerating apparatus for preserving food-stuffs, thecombination of a refrigerator cabinet, a cooling unit in the cabinet forabsorbing heat therefrom, a refrigerating mechanism for circulating arefrigerant through the cooling unit, and a control mechanism adjustableto a plurality of positions for cycling the mechanism to maintain thecooling unit at varying relatively low mean refrigerating temperatures,whereupon frost accumulates on the cooling unit, said control mechanismalso having at least one additional position of adjustment to effectcontinuous cycling of the mechanism to maintain a relatively high meanrefrigerating temperature in the cooling unit suflicient to remove orretard the accumulation of frost on the cooling unit, said lattertemperature being sufficiently low for preserving food-stuffs.

5. In a refrigerating apparatus for preserving food-stuffs, thecombination of a refrigerator cabinet, a cooling unit in the cabinet forabsorbing heat therefrom, a refrigerating mechanism for circulating arefrigerant through the cooling unit, a control mechanism adjustable toa plurality of positions for cycling the mechanism to maintain thecooling unit at varying relatively low mean refrigerating temperatures,whereupon frost accumulates on the cooling unit, said control mechanismalso having at least one additional position of adjustment to effectcontinuous cycling of the mechanism to maintain a relatively high meanrefrigerating temperature in the cooling unit sufficient to remove orretard the accumulation'of frost on the cooling unit, said lattertemperature being sufficiently low for preserving food-stuffs, andmanually adjustable means included in the control mechanism forobtaining either the relatively high or the relatively low refrigeratingtemperatures in the cooling unit.

6. In a refrigerating apparatus for preserving food-stuffs, thecombination of a refrigerator cabinet, a cooling unit in the cabinet forabsorbing heat therefrom, a refrigerating mechanism for circulating arefrigerant through the cooling unit, a control mechanism adjustable toa plurality. of positions for cycling the mechanism to maintain thecooling unit at varying relatively low refrigerating temperatures,whereupon frost accumulates on the cooling unit, said control mechanismhaving at least one additional position of adjustment to effectcontinuous cycling of the refrigerating mechanism to maintain a Irelatively high refrigerating temperature in the cooling unit sufficientto remove or retard the accumulation of frost on the cooling unit, saidlatter temperature being sufficiently low to preserve food-stuffs andsaid control mechanism also having another additional adjustment toprevent cycling of the refrigerating mechanism, and manually adjustablemeans associated with the control mechanism for obtaining either therelatively high or the relatively low refrigerating temperatures or forstopping the refrigerating mechanism.

'7. The method of operating a refrigerator for preserving food-stuffs,which refrigerator has a cooling unit in its cabinet maintained at arefrigerating temperature by a cyclically operated refrigeratingmachine, which method comprises DISCLAIM ER 1,934,608.J0hn'J. Bauman,

' dated November 7, 1933.

Springfield, Mass.

REFRIGERATOR OoNTRoL. Patent Disclaimer filed March'31, 1936, by theassignee,

' Westinghouse Electric ct Manufacturing Company. Herebg; enters thisdisclaimer to claims 1 to 5'inclusive and 7, of the above patent.

' I l Gazette April 21, 1.986.]

